Update 1:30pm Sunday:
Sunday late morning model runs still favor a shot of 2" to 4"+ range snowfall Monday morning between 3am and noon. Unless later model runs shift the system east, expect a snowy and slick AM rush hour Monday in the metro!
In the meantime a freezing rain advisory has been posted for most of eastern Minnesota and western Wisconsin. Icing may be light, but should cause a thin glaze ice layer that will make for slick roads & footing.
1205 PM CST SUN JAN 22 2012
...FREEZING RAIN ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT CST
* TIMING...PERIODS OF FREEZING DRIZZLE WILL CONTINUE THROUGH
MIDNIGHT BEFORE TRANSITIONING TO ALL SNOW.
* ICE ACCUMULATIONS...LESS THAN A TENTH OF AN INCH.
* OTHER IMPACTS...ANY UNTREATED ROADS...SIDEWALKS OR OTHER
SURFACES WILL BECOME COATED IN ICE AND SLIPPERY BY THE
A FREEZING RAIN ADVISORY MEANS THAT PERIODS OF FREEZING RAIN OR
FREEZING DRIZZLE WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR
SLIPPERY ROADS. SLOW DOWN AND USE CAUTION WHILE DRIVING.
One more major model run later tonight should firm up snowfall for Monday morning.
***Posted 10:47pm Saturday***
Here's a quick update based on the late Saturday evening model runs.
In addition to the chance of ice and sleet Sunday, both the NAM & GFS models (and others) are ramping up the notion of a rapidly deepening low pressure system Sunday night and Monday.
If they're accurate, (and I'm leaning that way) this could produce a 6-12 hour burst of decent snowfall in eastern Minnesota (including the metro) between midnight and noon Monday.
Based on what I'm seeing tonight, I think we need to raise awareness about the potential for significant snow in the metro late Sunday night and Monday morning. We could see several inches of snowfall from the Twin Cities and western Wisconsin north along I-35 toward Duluth and the Iron Range.
The latest model runs wrap up a low pressure system in eastern Iowa Sunday, then move the deepening system north through central Wisconsin into Lake Superior Monday.
That is an excellent track for producing significant snowfall in eastern Minnesota.
If Saturday night's model runs hold that track and intensity, that could produce anywhere from 2" to 4"+ of snow in the Twin Cities between midnight and noon Monday.
As the storm intensifies and slows down over Lake Superior, it could dump heavier snowfall totals (6"+?) on the Iron Range and much of northeastern Minnesota including Ely the North Shore.
Stay tuned for updates on this developing winter weather situation!